The Oxford Thesaurus An A-Z Dictionary of Synonyms - fanaticismn.

1) devotion, dedication, devotedness; infatuation, enthusiasm, fervour, zeal, obsessiveness, franticness, frenzy, hysteria: Her fanaticism for rock musicians is getting a bit out of hand. 2) monomania, single-mindedness, mania, madness, extremism, intolerance, bigotry, bias, partiality, prejudice, narrow-mindedness, close-mindedness: Some religious sects are characterized by virulent fanaticism.